Every single Yahoo account was compromised by hackers (VZ)

Yahoo's infamous hack already one of the worst in history  is even worse than previously thought.

All three billion of the user accounts it had in 2013 were affected by the security breach, the company, now owned by Verizon, said on Tuesday. Previously, the company estimated the hack affected one billion accounts.

In its statement, the company said:

"Subsequent to Yahoo’s acquisition by Verizon, and during integration, the company recently obtained new intelligence and now believes, following an investigation with the assistance of outside forensic experts, that all Yahoo user accounts were affected by the August 2013 theft." Verizon acquired Yahoo in June 2017.

The hacked user information included phone numbers, birth dates, security questions, and "hashed" passwords, the company said in a list of frequently asked questions on its website. The hacked information did not include passwords in clear text, payment card data, or bank account information, the company said.

However, the technique Yahoo used to "hash," or scramble, passwords on its site is an an outdated one that is widely considered to be easily compromised. So, it's quite possible people in possession of the hashed passwords would be able to unscramble them.

Yahoo said it is sending out email notifications to account holders it didn't previously determine were affected by the hack.

This story is developing. Check back here for updates.